1. Field of the Invention
The present invention relates to computer systems having field replaceable units, and more particularly, to a computer system having field replaceable units where signal and power connectivity can be established through the front or the back of the computer system.
2. Description of the Related Art
With the rapid growth and use of the world wide web, service providers such as telecommunications companies (telecoms) and internet service providers (ISPs) are experiencing rapid growth in the size of their data processing operations, while having to meet the high availability demands of the internet users. In this market, space is at a premium and system uptime is critical. Computer systems, often referred to as servers, need to meet the requirements of high performance, high availability, low profile systems at a competitive price.
Industry wide organizations have attempted to address some of these issues by adopting standards to make components interchangeable with ease. One of these standards is the peripheral component interconnect standard or PCI standard. The PCI standard is an industry standard which provides a high performance local bus architecture at a low cost. It is intended to be a common I/O component interface across different platforms. The PCI bus is not truly a local bus (i.e. One which enables data transfer between the processor and memory/cache subsystems) but is instead an intermediate bus which is coupled to the processor by a PCI bridge controller. Data can be transferred to the devices on the PCI bus through the bridge controller, which typically buffers the data and allows the processor to perform other tasks while the data is transferred to the target device at the most efficient rate possible.
Compact PCI or cPCI is another industry standard which is related to PCI. Compact PCI is a combination of several well developed technologies, including PCI bus technology, Eurocard mechanical technology (e.g. As used in VME bus systems), and a pin and socket connector technology. The combination of these technologies results in a rugged, reliable package for PCI devices.
The compact PCI standard also provides for several levels of hot swapping. Hot swapping refers to the installing or removing devices from a computer while the computer is operating. Hot swapping is useful because it allows components to be replaced or upgraded without necessitating any downtime in the system. This is particularly important in applications such as network servers, routers, voice mail servers and other systems that must be online all the time.
While the importance of ruggedizing individual system components is readily understood, it is similarly as important that the system in which these components are installed is likewise as robust. No matter how rugged the devices are, or how efficient the hot swapping methodology is, unless the system in which they are installed is rugged and highly available, the components will not work.
A server designed to the compact PCI standard must be as rugged as the individual components, and for the greatest market penetration, should be designed for deployment in the U.S., European and Asian markets. Consumers such as telecoms and ISPs further have high availability requirements of such a system. Customer requirements can further vary greatly. Many applications are compute intensive and many applications are I/O intensive. In some applications, the customer would like to deploy servers that meet both the compute intensive and I/O intensive applications. Moreover, in some geographical locations, the preference (or requirement) is that all field replaceable units (referred to as FRUs) be replaced from the front of the system, and all signal and power connectivity be made through the rear of the system. In other markets, all the FRUs as well as signal and power connectivity needs to be made from the front of the system. A further complication arises in this situation, because centrally located devices within the machine (for example midplanes and power filters) are also considered FRUs and must also be replaced from the front or back of the system.
It can thus be readily understood that there is a need for a general purpose server that is rugged, highly available and meets the varying requirements as described above.
To overcome the limitations described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, disclosed is a computer system comprising a chassis that houses one or more servers removably mounted in drawers in the computer system. The computer system further includes optional power and signal connectivity to the one or more servers through either the front or the rear of the machine.
Briefly stated, one embodiment of a computer system according to the present invention includes a chassis that houses one or more individual computer servers which reside in drawers or subchassis. The drawers may be half the width of the chassis, or may be one fourth the width of the chassis. The chassis may house one to four of the drawers, in various combinations. The servers further comprise a plurality of field replaceable units which may be accessed and replaced from the front of the server. The drawer that houses the servers includes cable routing brackets and power supply units that allow power to be supplied through the front of the machine. Similarly, a power supply input on the rear of the drawer allows for power to be supplied from the rear of the machine. An internal power filter allows the power supply to operate in either condition. Signal connectivity is made through the front or rear of the drawer, where the drawer mates with a midplane in the chassis.
The server is further comprised of a central processing unit, power supply, storage and fan trays for cooling the machine. The upper portion or upper bay of the drawer includes one or more expansion card slots, which may be compact PCI card slots. The drawers include slide handles which allow the drawers to be slideably installed into the chassis. Most field replaceable units mate into the system midplane and may be serviced or replaced from the front of the machine. Transition cards in the rear of the chassis allow for signal connectivity to these peripheral devices to be made through the rear of the machine.
Accordingly, the computer system of the present invention is suited for the various environments where front or rear cable access may be required. Further, the computer system of the present invention is comprised of a plurality of field replaceable units that follow industry standards, are robust and easy to service. These and other advantages of the present invention will be more readily understood in the following detailed description accompanied by the following drawings.